# Pool:线程池
from multiprocessing import Pool
import os, time, random


def long_time_task(name):
    print("Run task %s (%s)" % (name, os.getpid()))
    start = time.time()
    time.sleep(random.random() * 3)
    end = time.time()
    print("Task %s run %0.2f seconds." % (name, end - start))

if __name__ == '__main__':
    print("Parent process %s." % os.getpid())
    p = Pool(4)
    for i in range(5):
        p.apply_async(long_time_task, args=(i,))
    print("waiting for all subprocess done..")
    p.close()
    p.join()
    print("all subprocess done.")
